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Surface structural alteration of multi-walled carbon nanotubes decorated by nickel nanoparticles based on laser ablation/chemical reduction methods to enhance hydrogen storage properties
摘要： The catalytic effect of nickel is addressed to decorate the multi-walled carbon nanotubes for the purpose of hydrogen storage. The hydrogen sorption/desorption are investigated using the volumetric technique. Nickel nanoparticles are distributed on the surface of nanotubes using the laser ablation/chemical reduction treatments. The hydrogen uptake is elevated at higher nickel population up to a certain value and then experiences a significant drop for larger nickel content. The laser treatment is accompanied by the induced pores around nanotubes. This gives rise to the creation of the larger pores at higher laser doses leading to decrease the hydrogen trapping. Despite the pore size distribution strongly alters during both synthesis methods, however the abundance of small pore size in laser treatments is relatively higher than the that of the other technique. In comparison, the laser ablation demonstrates a relatively smaller desorption temperature against chemical one, mainly owing to the formation of larger pore size/volume. Generally, the hydrogen trapping efficiently takes place in the laser treated samples against chemical reduction method. The highest value of hydrogen storage ~1% (0.6% weight) is corresponding to 12.3% (13% weight) of nickel loading via the laser ablation (chemical reduction).
关键词： Hydrogen uptake,Nickel nanoparticles,Laser ablation,Chemical reduction,Pore size
更新于2025-09-23 15:22:29
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Acceleration of tungsten doping on vanadium dioxide (VO2) by alkali species
摘要： The monoclinic vanadium dioxide, VO2(M), undergoes reversible phase transition from monoclinic (semiconductor) to tetragonal (metal), which exhibits a good thermochromic property. VOSO4, as a vanadium source, is easy to handle produces VO2(M) under mild condition in the presence of alkali species. In this study, the effects of the additions of NH4HCO3, NH3·H2O, and NaOH on the VO2 crystal formation with/without tungsten doping for thermochromicity were investigated. NaOH, the strongest base of the three, provided the strongest and narrowest x-ray diffraction peak, while NH4HCO3, the weakest base, provided the opposite. Interestingly, for the tungsten doping to adjust the transition temperature, the use of NH4HCO3 was more suitable due to the possibility of a slow crystal frame formation as compared to the use of NaOH.
关键词： Sodium hydroxide,Vanadium dioxide,Ammonium hydrogen carbonate,Ammonium hydroxide,Tungsten doping
更新于2025-09-23 15:22:29
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Photocatalytic hydrogen evolution assisted by aqueous (waste)biomass under simulated solar light: Oxidized g-C3N4 vs. P25 titanium dioxide
摘要： Oxidized graphitic carbon nitride (o-g-C3N4) and Evonik AEROXIDE? P25 TiO2 were compared for lab-scale photocatalytic H2 evolution from aqueous sacrificial biomass-derivatives, under simulated solar light. Experiments in aqueous starch using Pt or Cu–Ni as the co-catalysts indicated that H2 production is affected by co-catalyst type and loading, with the greatest hydrogen evolution rates (HER) up to 453 and 806 μmol g?1 h?1 using TiO2 coupled with 3 wt% Cu–Ni or 0.5 wt% Pt, respectively. Despite the lower surface area, o-g-C3N4 gave HERs up to 168 and 593 μmol g?1 h?1 coupled with 3 wt% Cu–Ni or 3 wt% Pt. From mono- and di-saccharide solutions, H2 evolution was in the range 504–1170 μmol g?1 h?1 for Pt/TiO2 and 339–912 μmol g?1 h?1 for Cu–Ni/TiO2, respectively; o-g-C3N4 was efficient as well, providing HERs of 90–610 μmol g?1 h?1. The semiconductors were tested in sugar-rich wastewaters obtaining HERs up to 286 μmol g?1 h?1. Although HERs were lower compared to Pt/TiO2, a cheap, eco-friendly and non-nanometric catalyst such as o-g-C3N4, coupled to non-noble metals, provided a more sustainable H2 evolution.
关键词： Biomass,Graphitic carbon nitride,Hydrogen,Photocatalysis,Solar light,Titanium dioxide
更新于2025-09-23 15:22:29
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One-step synthesis of hierarchical AuNPs/Cd0.5Zn0.5S nanoarchitectures and their application as an efficient photocatalyst for hydrogen production
摘要： The hierarchical AuNPs/Cd0.5Zn0.5S hybrids are directly fabricated via a facile one-step in-situ hydrothermal method. The as-prepared AuNPs/Cd0.5Zn0.5S hybrids demonstrate superior photocatalytic performance toward hydrogen production under visible light irradiation. The hydrogen evolution rate of the 5 wt% AuNPs/Cd0.5Zn0.5S synthesized with in-situ hydrothermal method can be 7.1 times greater than that of pure Cd0.5Zn0.5S and as much as 2.5 times of 5 wt% AuNPs loaded Cd0.5Zn0.5S synthesized with photodeposition method. Systematical investigations reveal that the enhanced photocatalytic performance of the one-step in-situ prepared AuNPs/Zn0.5Cd0.5S can be attributed to the inherent SPR effect and favorable electron transfer properties of AuNPs, as well as the rational hierarchical nanoarchitectures that allow AuNPs to be uniformly incorporated into Zn0.5Cd0.5S matrix. This one-step in-situ fabrication method provides a simple and efficient route to synthesize well-defined heterocatalysts.
关键词： AuNPs/Cd0.5Zn0.5S,Photocatalysis,Hydrogen evolution,SPR,One-step
更新于2025-09-23 15:22:29
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Medium viscosity effect on fluorescent properties of Sn(IV)-tetra(4-sulfonatophenyl)porphyrin complexes in buffer solutions
摘要： Supramolecular triads consisting of hydrophilic Sn(IV)-tetra(4-sulfophenyl)-porphyrin and two axial guests such as propylphenol, tyrosine, and 2-(2-hydroxyphenyl)-benzoxazole were synthesized. The structures of synthesized complexes were identified by experimental spectroscopic and quantum-chemical simulation methods, and their fluorescent properties were studied in various viscosity media (mixed phosphate buffer-glycerin solvents of different composition). The effect of axial ligand structure on the fluorescent properties of these triads (due to the hydrogen bonding or π-π stacking between the components of ?host-guest? systems) is discussed. The potential use of synthesized complexes as environmental probes of local viscosity is proposed.
关键词： synthesis,ROESY,fluorescent properties,hydrogen bonding,DOSY,2D NMR,DFT,viscosity,Sn(IV)-porphyrins
更新于2025-09-23 15:22:29
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Organic-inorganic hybrid perovskite – TiO2 nanorod arrays for efficient and stable photoelectrochemical hydrogen evolution from HI splitting
摘要： Solar-driven photoelectrochemical (PEC) hydrogen production offers a promising solution to simultaneously tackle the global energy crisis and the environmental pollution. Herein, we report a PEC cell of organic-inorganic hybrid perovskite (methylammonium lead iodide, MAPbI3)-TiO2 nanorod array (TNAs) for efficient and stable hydrogen evolution in aqueous hydrogen iodide (HI) solution. The built-in electric field created across the MAPbI3-TiO2 junction is able to efficiently separate the electron-hole pairs photogenerated in MAPbI3 with electrons quickly injected from MAPbI3 to TiO2, which are then transported along the one-dimensional TiO2 nanorod channels to the counter electrode to reduce proton to evolve hydrogen. The optimized MAPbI3-TNA PEC cell exhibits a high photocurrent density of 1.75 mA cm-2 at 0.14 V (vs. Ag/AgCl) under AM 1.5G illumination, which is able to stably produce molecular hydrogen at a rate of 33.3 mmol cm-2 h-1 for more than 8 h.
关键词： Perovskite,Nanorod arrays,Hydrogen evolution,Heterojunction,Photoelectrochemical
更新于2025-09-23 15:22:29
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Azaindole-BODIPYs: Synthesis, fluorescent recognition of hydrogen sulfate anion and biological evaluation
摘要： The synthesized and sensing capability of two novel azaindole substituted mono and distyryl BODIPY dyes against bisulfate anion were reported. Structural characterizations of the targeted compounds were conducted by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, 1H and 13C NMR spectroscopies. Photophysical properties of the azaindole substituted BODIPY compounds were investigated employing absorption and fluorescence spectroscopies in acetonitrile solution. It was found that the final compounds 3 and 4 exhibited exclusively selective and sensitive turn-off sensor behavior on HSO4- anion. Additionally, the stoichiometry ratio of the targeted compounds to bisulfate anion was measured 0.5 by Job’s method. Also, density function theory was performed to the optical response of the sensor for targeted compounds. Furthermore, the cytotoxicity of Azaindole-BODIPYs were examined against living human leukemia K562 cell lines.
关键词： Fluorescence,Azaindole,K562 cell lines,Borondipyrromethenes,DFT,Chemosensor,hydrogen sulfate,Anionsensor
更新于2025-09-23 15:22:29
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Effect of hydrogen peroxide on photoelectric properties of high-transmittance FTO films prepared by spray pyrolysis
摘要： The FTO film prepared by spray pyrolysis has low efficiency and most of the precursors are discharged in the form of waste steam. According to the high oxidation property of H2O2, it is attempted to improve the film formation rate by changing the concentration of H2O2. Fluorine-doped SnO2 (FTO) thin films with high transmittance were prepared by spray pyrolysis using monobutyltin trichloride as the tin source and ammonium fluoride as the fluorine source. Different concentrations of hydrogen peroxide (0-0.08M) are added to the precursor solution. In this paper, we studied the effect of hydrogen peroxide on the structure, surface morphology and photoelectric properties of FTO thin films. The results show that the growth rate of the FTO films increased from 6.04 nm/s to 8.36 nm/s with the increase of H2O2 concentration from 0 to 0.08 M. The optimum preparation process is H2O2 concentration controlled at 0.04M, and FTO thin films suitable for solar cells are prepared. It has excellent performance parameters; carrier concentration:2.74*1021cm-3; carrier mobility:55.92 cm2 V-1s-1; photoelectric quality factor:2.66×10-3·Ω-1and the average transmittance of visible light: 79.87%. At the same time, increasing H2O2 concentration leads to narrowing of optical band gap. Adding appropriate hydrogen peroxide concentration can improve the film production rate and obtain excellent quality films.
关键词： Tin oxide,Preferred orientation,Hydrogen Peroxide,Optoelectronic performance
更新于2025-09-23 15:22:29
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A novel “turn-on” mitochondria-targeting near-infrared fluorescent probe for H2S detection and in living cells imaging
摘要： Hydrogen sulfide (H2S) has been considered to be involved in cytoprotective processes and redox signaling. It is very meaningful to track and analyze it in mitochondria. Herein, we report a novel “turn-on” mitochondria-targeting near-infrared fluorescent probe (Mito-NIR-SH) for detection of H2S in living cells, which was designed and synthesized by introducing 2,4-dinitrophenyl as fluorescence quenching group and H2S response moiety into Changsha near-infrared fluorophore (CS-OH). The structure of the fluorophore and the probe were characterized by 1H NMR, 13C NMR and mass spectrometry. Meanwhile, Mito-NIR-SH could quantitatively detect H2S at concentrations ranging from 0 to 30 μM with a detection limit as low as 89.3 nM, showing good chemical stability, fast “turn-on” response, selectively mitochondrial location, as well as high sensitivity and selectivity toward H2S. Based on this, it was successfully applied to imaging exogenous and endogenous H2S in living HeLa cells via confocal fluorescence microscopy.
关键词： High sensitivity and selectivity,Near-infrared fluorescent probe,Hydrogen sulfide,Mitochondria-targeting,Bioimaging
更新于2025-09-23 15:22:29
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Nanostructuring Strategies To Increase the Photoelectrochemical Water Splitting Activity of Silicon Photocathodes
摘要： Photoelectrochemical water splitting is a promising route for sustainable hydrogen production. Herein, we demonstrate a photoelectrode motif that enables a nanostructured large-surface area electrocatalyst without requiring a nanostructured semiconductor surface with the goal of promoting electrocatalysis while minimizing surface recombination. We compare the photoelectrochemical H2 evolution activity of two silicon photocathode nanostructuring strategies: (1) direct nanostructuring of the silicon surface and (2) incorporation of nanostructured zinc oxide to increase the electrocatalyst surface area on planar silicon. We observed that silicon photocathodes that utilized nanostructured ZnO supports outperformed nanostructured silicon electrodes by ～50 mV at open circuit under 1 sun illumination and demonstrated comparable electrocatalytic activity.
关键词： photocathodes,silicon nanowires,hydrogen evolution,molybdenum disulfide,zinc oxide nanowires,photoelectrochemical water splitting
更新于2025-09-23 15:22:29